You screen, I screen, we all screen —

What do we actually know about the risks of screen time and digital media?

Some tentative links are in place, but many crucial details are fuzzy.

The plague of causation

Hanging over the entire debate is the question of how video games and aggression are linked. The arguments typically focus on an obvious answer: violent video games lead to aggression. But it could be the other way around: aggressive kids like violent video games. Or even a tangle: aggressive kids like violent video games, and that makes them more aggressive, which increases their appetite for violent media, and so on.

The gold standard for answering this kind of question is a randomized controlled trial: randomly assign kids to two groups, give one group of kids access to all the gore they want, keep the other playing innocent games, and check in on their delinquency in a few years. Of course, that isn’t going to fly with an ethics committee, and the alternatives can, at best, point and wink suggestively. Check on kids’ aggression rates at a certain age, ask about their game exposure, and check in on their aggression later to see if the two could be linked. Or get a bunch of people in a lab playing something violent, and then test something to do with their aggression levels.

Hull thinks the evidence from this kind of work is stacking up in favor of the obvious answer—violent games lead to aggression. He readily acknowledges that the reverse causal story is entirely possible, but “I do believe in parsimony,” he says wryly. “The [simplest] explanation that fits the most data ought to be given more weight.”

That issue of causation is a plague for studies beyond aggression, too. In reviewing the evidence on media and ADHD, Dimitri Christakis and his colleagues write that, no matter how well-controlled observational studies are, they can’t provide strong evidence of a causal relationship. A link between media and ADHD is just that: evidence that the two move together in concert. It can’t tell us whether media fuzzes up the wiring in a young brain or whether kids with ADHD behaviors are more readily drawn to media.

In an effort to shed some light on the issue, Christakis and his colleagues exposed baby mice to an unpleasant disco of “excessive sensory stimulation” involving colored lights and cartoon audio for six hours every day over 42 days. After a ten-day break, the researchers put the overstimulated mice through their paces in a series of tests like maze navigation and object recognition and compared their results to mice that hadn’t been exposed to the cartoons and light.

They found that the overstimulated mice performed worse than the control group, suggesting that “overstimulated mice have outcomes that are consistently worse than those reared in what might be deemed an understimulating one,” they write.

“It’s a classic example of over-interpretation from animal models,” says Przybylski. Although animal models can be useful to explore something that would be unethical to do in humans, he explains, it’s dangerous to rest too much on the comparison. In this case, the researchers suggest that children being exposed to fast-paced media, like exciting and activity-filled kids’ TV, alters the trajectory of brain development. While the media exposure did seem to affect how mice performed in their tests, it’s not clear whether the sound and lights is the equivalent of a TV show or whether we can draw a straight line from the mice to human ADHD.

Enlarge/ How do you classify a longtime, ever-evolving show like Sesame Street?

Children's Television Workshop/Courtesy of Getty Images

A messy library

As for the literature on ADHD in humans—well, it’s “more theoretically than empirically grounded,” write Ine Beyens and colleagues in their review of 40 years of research on the question. That is, there are plenty of hypotheses for how screen media could potentially increase the risk of ADHD, but solid support for those hypotheses is harder to come by.

Much like the research on aggression, deciding precisely what to measure and how to measure it is a series of rabbit holes. Experiments looking at the effects of fast-paced media need to decide exactly what pacing is—is it camera angle changes, camera cuts, scene changes, or voice changes? They need to decide on what counts as fast or slow pacing: one episode of Sesame Street might be faster-paced than another, but given the slow overall pace of the program, does it still count as fast? And how do you accurately figure out how much fast-paced media kids are exposed to?

Further Reading

Possibly because of this kind of complication, the field is still wide open, write Beyens and colleagues. It’s an assessment echoed by Melina Uncapher and Anthony Wagner’s review of the research on media multi-tasking and attention: “[the literature] provokes more questions than it answers,” they write. On almost every question they explore, some results come up positive, but others are inconclusive.

The field is struggling with problems faced by science as a whole, says Przybylski: “We’re realizing that a lot of what we see is influenced by publication bias.” Experiments are done in small groups that make unreliable findings more likely; researchers dive headfirst into their data looking for exciting results, rather than to test a hypothesis; and results that are confusing, or weird, or boring can easily languish without publication. The only real way out of the quagmire is for the field to commit to practices designed to correct these problems.

But there are bigger philosophical issues, too, Przybylski says. “This isn’t nicotine. In tobacco there are carcinogens and addictive elements; there’s a mechanism that connects tobacco to easily observable health outcomes.” Screens are nowhere near as simple and can’t be treated as a simple dose of something good or bad, he says.

And there are risks to getting this wrong. Parents, adamant about limiting their kids' screen time, could push their kids toward the choice of either lying about their device use or being cut off from their social lives. There are also risks like the ones Markey worries about: focusing on tiny effects while more important explanations for problems are ignored.

So, is digital media a concern for developing minds? There’s no simple answer, in part because the uses of media are too varied for the question to really be coherent. And, while some research results seem robust, the catalogue of open questions is dizzying. Answering some of those questions needs not just a leap in research quality, but, argues Przybylski, a reframing of the question away from the way we think about tobacco and toward the way we think about information: “What are the most effective strategies parents can employ to empower young people to be proactive and critical users of technology?”

Promoted Comments

I think the comment about, "we don't talk about food-time" is the best comment to be made on research into this topic. As a practitioner who works with childhood behavioral disorders (including severe aggression) I get to see the obvious correlation between "screen time" and aggressive behavior and mood regulation difficulties. However, I cannot say it's a clearly casual relationship and I don't categorize all use of electronics as "screen time." The lack of nuance is too imprecise to guide effective intervention strategies.

Kids with significant emotional or behavioral concerns are also more likely to seek escape from frequent unpleasant (punitive) experiences. There are many ways to achieve escape, but watching videos and playing games are certainly highly effective and readily available. Withdrawing those forms of release (negative reinforcement) provokes irritation and sometimes overt aggression. This combines to make it look like the videos and games are the cause instead of simply a related component of the pattern of behavior.

The nature of screen usage is also worth considering. I haven't yet come across a kid with behavioral concerns who is binge-watching Mister Rogers (would be really surprising!). But rather than looking for causes, I find I can better spend my time trying to understand the many factors contributing to a pattern of maladaptive behavior and trying to use that information to develop a plan for teaching and reinforcing a more effective pattern of behavior.